Dihydrocarbyl tin maleic acid esters and their use as pvc stabilizers



United States Patent M 39/ 62,318 U.S. Cl. 26045.75 7 Claims Int. Cl. (108g 45/ 6'2 ABSTRACT OF THE DISCLOSURE In accordance with certain of its aspects this invention relates to novel compositions and to a novel process for stabilization of vinyl chloride resins against heat and light by adding to vinyl chloride resin 0.5 to by weight of a stabilizer consisting essentially of an organotin compound having the general formula R/ OOCCH=CHOOORz wherein R represents a member selected from the group consisting of alkyl containing from 1 to 18 carbon atoms, aryl and benzyl radicals and CR and CR each represents a member selected from the group consisting of (a) the organic residue of an alcohol containing 816 carbon atoms and including an aromatic substituent in one of the on and 6 positions, the rate of autooxidation of said alcohol being more than 20.0 10 /l. sec. at a temperature of 80 C. in the presence of benzoyl peroxide as an initiator, and (b) the organic residue of a phenol containing 7-24 carbon atoms and including 1-3 substituents containing from 1-8 carbon atoms selected from the group consisting of alkyl and alkoxy radicals said phenol having an oxidation potential of less than 0.9 volt.

This invention relates to the stabilization of vinyl chloride resins.

Recently various stabilizers have been employed as stabilizers of polyvinyl chloride resins; for example, tin compound stabilizers such as diorganotin dilaurate, diorganotin maleate, or diorganotin bis(ester maleate), etc., have been used commonly. In the process of stabilization of vinyl chloride resins employing the conventional organotin compounds, however, it was necessary to prevent oxidative deterioration by employing an antioxidant. Because of this fact, there were many problems in accomplishing the full purpose for using the conventional stabilizers.

Conventionally used diorganotin maleates or diorganotin bis(ester maleate), which contain dienophilic maleic acid residues or dienophilic ester maleate residues in their molecules, were very valuable as stabilizers, since they act sensitively on the double bond formed during treatment of the vinyl chloride resins. As is well known to those skilled in the art, since vinyl chloride resins, e.g. polyvinyl chloride, copolymers of vinyl chloride with vinyl acetate, polybutadiene, copolymer of acrylonitrile and styrene, or terpolymer of acrylonitrile, styrene and butadiene, vinyl chloride mixed and modified with up to by weight chlorinated polyolefin etc., may be oxidized during or after treatment, they have imperfections with respect to color change which occurs during treatment or which change the physical properties of manufactured goods with the passage of time.

In order to prevent this oxidation diorganotin bis(ester maleate) was used conjointly with a hindered phenol, so

3,433,763 Patented Mar. 18, 1969 that the favorable stabilization including prevention of oxidation might be attained. However hindered phenols may be fairly sublimated and dissipated at the general temperature for treatment of vinyl chloride resins, i.e. above 185 C., and furthermore they do not fully maintain their stabilizing effect against changes in the manufactured goods with the passage of time due to heat or light over a period of long hours at room temperature or 60 C.

These phenomena are generally considered undesirable because of the generally few number of carbon atoms in the substituents of a typical antioxidant, a hindered phenol, and also because the hydroxy group is stericly hindered by the influence of an alkyl radical.

It is an object of this invention to provide diorganotin bis(ester maleates) having ester maleate radicals which contain alcohol or phenol residues which provide a high degree of stabilization characteristics including remarkable dienophilic properties and antioxidative properties for vinyl chloride resins. Other objects of this invention will be apparent on inspection of the following description.

In accordance with certain of its aspects this invention relates to a novel process for stabilization of vinyl chloride resins against heat and light by adding to vinyl chloride resin 0.5 to 5% by weight of a stabilizer consisting essentially of an organotin compound having the general formula R OOCCH=CHCOOR1 R/ \OOCCH=CHCOOR2 wherein R represents a member selected from the group consisting of alkyl containing from 1 to 18 carbon atoms, aryl and benzyl radicals and 0R and CR each represents a member selected from the group consisting of (a) the organic residue of an alcohol containing 8-16 carbon atoms and including an aromatic substituent in one of the on and [3 positions, the rate of autooxidation of said alcohol being more than 20.0 l0- /l. sec. at a temperature of C. in the presence of benzoyl peroxide as an initiator, and (b) the organic residue of a phenol containing 7-24 carbon atoms and including 1-3 substituents containing from 1-8 carbon atoms selected from the group consisting of alkyl and alkoxy radicals said phenol having an oxidation potential of less than 0.9 volt.

The diorganotin bis(ester maleate) of the instant invention may have superior properties as a stabilizer of vinyl chloride resin. The ester maleate radical of its molecule vpossesses not only dienophilic property but also possesses an antioxidative property because of its containing an oxidizable substituted phenol residue or an oxidizable alcohol residue in the form of ester. Furthermore the stabilizing compound does not sublirnate and dissipate at the temperature of treatment of vinyl chloride resins.

The parent alcohol which may meet aforesaid conditions may possess an aromatic substituent especially in the a or [3 position of the alcohol. Furthermore, the alcohol residue and the phenol residue which may be present in the diorganotin compound to be employed in practice of this invention also may have the total number of carbon atoms of said alcohol and phenol limited in connection with physical properties desired for processing conditions and compatibility with the resins.

In accordance with certain aspects of this invention novel stabilizing compounds for vinyl chloride resins may be provided which may be characterized by the general formula Illustrative R, CR and R in the general formula of diorganotin-bis-(ester maleate) may be as follows: Typical R may include methyl, butyl, octyl, phenyl, benzyl, etc. Typical CR and CR may include organic residues of 8 to 16 carbon parent alcohols bearing an 5 aromatic substituent in one of the 0c and 5 positions, such as 2-fi-naphthyl carbinols, l-(oc-alld B-naphthyl) ethyl a1- cohols, Z-(a-and B-naphathyl) ethyl alcohols, a-phenylethyl alcohol, hydroxy cinnamyl alcohols, diphenyl Typical solvents which may be employed in the above process include benzene, toluene, etc. The half-acid ester maleate may be recovered prior to reaction with the organotin compound and that reaction carried out in the absence of solvent. Alternatively, the reaction with organotin compound may continue in the presence of solvent.

The parts described in the following examples are parts by weight.

carbinol, p-methylbenzyl alcohol, and residues of 7 to 24 10 EXAMPLE 1 carbon parent phenols bearing 1 to 3 substltuents selected from the group Consisting of alkyl and alkOXY eehteihhlg Preparation of dibutyltin bis(2-t-buty1-4-methoxy- 1 to 8 carbon atoms, such as 2-t-octyl phenol, 2,6-di-th l l y -pl Y P 90 parts (0.5 mole) of 2-t-butyl-4-methoxy phenol, 49 f y y P 'P Y Y P 15 parts (0.5 mole) of maleic anhydride and 433 parts of tY 1methY1 P I PY y P toluene may be placed in a three-necked flask, heated to dlmethyl Phenol, and Y P -h- 110 C. and stirred for about 2.5 hours thereby obtainhexyl phenol, Each R group y be the same or ing as a transparent yellow liquid 2-t-butyl-4-methoxyfefent, Preferably h y the Same 1 and 2 y phenyl maleate. 62 parts (0.25 mole) of dibutyltin oxide be the Same dlffereht; Preferably too y 8Ie the and an additional 260 parts of toluene may be added to same. react with the maleate caster and the mixture heated unyp 3 p e pa s) wi y be der reflux with stirring until water produced in the rep y m the Preehee 0f thls lhvehtlon Include; action is removed. The toluene solvent may then be redibutyltin bis(wphmylethyl maleate) moved by heating in vacuo, thereby yielding 183 parts dioctyltin bis[2-( 8-naphthyl) ethyl maleate] 5 (93.5%) of dibutyltin bis(Z-t-butyl-4-methoxyphenyl dioctyltin bis(o methylbenzyl maleate) maleate), a dark brown-colored viscous liquid. The tin dibutyltin bis(o methylbenzyl maleate) content calculated for the product is 15.15% and that dimethyltin bis[1-(a-naphthyl) ethyl maleate] found 15 dioctyltinbis[1-(,B-naphthyl)ethyl maleatel] EXAMPLE 2 diphenyltin bis(p-hydroxyclnnamyl maleate) di h 'l i bi (di h 1 h 1 l Preparation of dibutyltin b1s(o-methylbenzyl maleate) dibutyltin bis(fl-naphthylmethyl maleate) dibutyltin bis(z t octylphenyl maleate) 39428.9 parts (0.4 mole) of D ,L-o-meth ylbenzyl alcohol, parts (0.4 mole) of malelc anhydride and 260 parts dibenzyltm b1s(4 phenyl or naphthylmethyl maleate) of toluene ma be mix di H k a d he t d d d dibutyltin bis(2,6-di-t-butyl-4-methylphenyl maleate) for 1 ho r g r b s l as I dibutyltin bis(2,6-di-t-butyl-4-methoxyphenyl maleate) u e 6 y ng i enzy ma ea dibutyltin bis(zlldimethylphenyl maleate) 49.8 parts (0.2 mole) of dibutyltin oxide may be added dibutyltin bis(2,4-di-t-butyl-6-methylphenyl maleate) to dread gvlth F ff f i f i fi dibutyltin bis(2-t-butyl-4-methoxyphenyl maleate) un ux W1 S 1 Wa er pro uce m dioctyltin bis(2 4 6 trimethylphenyl maleate) 40 action is removed. The toluene solvent may then be redimethyltin bis(2,6-diisopropyl-4-ethylphenyl maleate) moved by heatmg vgcuo thereby yleldmg 125 parts dibenzylfin bis(z 6 di t butylphenyl maleate) (92.8%) of dibutyltin b1s(o-methyl-benzyl maleate). The (butyl) (octyl) bis(wphenylethyl maleate) tin content calculated for the product is 17.65% and that found is 17.40%. gl i (a phenylethyl maleate) (p methylbenzyl 5 Other organotin bis(ester maleates) of the invention th such as dioctyltin b1s[1-(fl-naphthyl) ethyl maleate], (bggr llgyfrneafiglgtmw Phenylethyl maleate) (P me yl g y i g T i Y i sZi-i ii ){jg a ts gi Egg? imetypeny maeate iuty in is ,-1-t-uy-- dwctyltm b1S(246 tn n hexylphenyl maleate) methylphenyl maleate), and dibutyltin bis(2-t-butyl-4- The organotin compounds of this invention may be methoxyphenyl maleate) may be prepared in a manner prepared by mixing in an inert solvent maleic anhydride similar to that of the above examples by reacting the ap with a compound selected from the group consisting of an propriate alcohol or phenol with maleic anhydride and alcohol having 8 to 16 carbon atoms, which includes an reacting the ester thereby formed with the appropriate aromatic substituent in one of the a and 3 positions, the diorganotin oxide. rate of autooxidation of the alcohol being more than EXAMPLE 3 20.0X10' /l. sec. at a temperature of C. 1n the 0 presence of benzoyl peroxide as an initiator and a phenol Dibutyltln bis(ester maleate) represented in Table 1 having 7 to 24 carbon atoms which includes '1 to 3 subas stabilizer may be separately added in amount of 3 stituents selected from the group consisting of alkyl and parts by weight to parts by weight of vinyl chloride alkoxy containing 1 to 8 carbon atoms, the oxidation 60 resin and sheets, having a thickness of 0.5 mm., may be potential of the phenol being less than 0.9 volt; heating made by milling on a mixing roll at surface temperature mixture thereby forming ester malete; reacting said ester of C. The vinyl chloride resin may have a specific maleate with (diorganotin) oxide thereby forming digravity of 1.40, a Shore Durometer D hardness of 80 and organotin bis(ester maleate); and recovering said dian ultimate tensile strength of 7000 p.s.i., such as that organotin bis(ester maleate). 65 sold under the trademark Geon 103 EP.

TABLE I At C. after 2 hours At 65 C. after 48 hours Stabilizer Absorption Absorption Color tone of carbonyl Color tone of carbonyl group group Dibutyltin bis-(methyl maleate), control Yellow Occurred. Light yellow Occurred. Dibliltylghi1"gliggatert-butylA-methoxy- Light ye1low Scarcely. Colorless Scarcely.

p any n 3 parts of dioctyltin bis(ester maleate) described in Table 2 as stabilizer and 0.5 part of liquid paraffin may be added to 100 parts of the vinyl chloride resin as in Example 3 and mixed with 15% by weight of chlorinated polyethylene, followed by milling on a mixing roll at surface temperature of 165 C. for 2 hours, and a similar test to that of Example 3 run. Results so obtained are shown in Table 2.

1 part of stearamide and 3 parts of dibutyltin bis (ester maleate) described in Table 3 may be added to 100 parts of copolymer of vinyl chloride and vinylidene chloride, and films which have a thickness of 0.3 mm. made by use of an extruder. The induction period of oxygen absorption for each of these films at 60 C. may be determined by infra-red absorption spectrum analysis of the carbonyl group. Table 3 indicates the values when the induction period of oxygen absorption of dibutyltin bis(methyl maleate) control as stabilizer is regarded as 1.

TABLE 3 Induction period of oxygen absorption Stabilizer: at 60 C. Dibutyltin bis(rnethyl maleate, control 1 Dibutyltin bis(2,4-dimethyl phenyl maleate) 25 Dibutyltin bis(2,4-di-t-butyl 6 methyl phenyl maleate 28 Dibutyltin bis(2' t butyl 4 methoxy phenyl maleate) 40 Although this invention has been disclosed by reference to various specific examples, it will be apparent to those skilled-in-the-art that various modifications and changes may be made thereto which fall within the scope of this invention.

What is claimed is:

1. A stabilized vinyl chloride resin composition containing vinyl chloride resin and 0.5-5 by weight of a stabilizer consisting essentially of an organotin compound having the general formula:

wherein R represents a member selected from the group consisting of alkyl containing 1-18 carbon atoms, phenyl, and benzyl radicals, and R and R each represent a member selected from the group consisting of l-(a-naphthyl) ethyl, l-(B-naphthyDethyl, 2-(a-naphthyl) ethyl, 2-(13- naphthyl)ethyl, cc phenylethyl, hydroxycinnamyl, pmethyl-benzyl, napthobenzyl, benzohydryl, 2-t-octyl phenyl, 2,6-di-t-butyl-p-cresy1, 2,6-di-t-butyl-4-methoxy phenyl, 2,4-di-t-butyl-6-methyl phenyl, 2-tbutyl-4-methoxy, phenyl, 2,4,6-trimethyl phenyl, 2,6-diisopropyl-4- ethyl phenyl, 2,4-dimethylphenyl, 2,6-di-t-buty1 phenyl, and 2,4,6-tri-n-hexylphenyl radicals.

2. A stabilized vinyl chloride resin composition as claimed in claim 1 wherein said organotin compound is dibutyltin bis(2-t-butyl-4-methoxyphenyl) maleate.

3. A stabilized vinyl chloride resin composition as claimed in claim 1 wherein said organotin compound is dioctyltin bis[1-(fl-naphthyl) ethyl maleate].

4. A stabilized vinyl chloride resin composition as claimed in claim 1 wherein said organotin compound is dioctyltin bis(o-methylbenzyl maleate).

5. A stabilized vinyl chloride resin composition as claimed in claim 1 wherein said organotin compound is dibutyltin bis(2,4-dimethyl phenyl maleate).

6. A stabilized vinyl chloride resin composition as claimed in claim 1 wherein said organotin compound is dibutyltin bis(2,4-di-t-butyl-6-methyl phenyl maleate).

7. A stabilized vinyl chloride resin composition as claimed in claim 1 wherein said organotin compound is dibutyltin bis(2-t-butyl4-methoxy phenyl maleate).

US. Cl. X.R. 260-4297, 45.95 

